[DeTomaso] Slow cranking when hot

Jeff Cobb jeffcobb1 at me.com
Sat Jul 15 08:15:50 EDT 2017


The easiest test is to connect the jumper cables as a ground from battery to block when it is slow to turn.
You should see a spark while cranking and the rotational speeds will vary.
Simple cranking amp draw test will tell where you flaw is.
Also after long slow turn over, does the negative cable heat up?
Is the negative cable rubber coating melted/bubbled by the ends, indicates too much heat from an undersized wire.
Also connect a volt meters hot lead to your block and try to start it when this flaw is there. 
Touch you ground lead to a body ground, subframe ground and to the battery negative. Do you have any voltage readings? 
If so, then you have a weak ground, not an undersized, ground.

If none of these test improves your flaw then your battery and or starter are bad as long as your timing is not too far advanced.

I had a slow turn over on my Mangusta till we found that the bell housing bolts to the transaxle were loose. 
You could see arcing at bolts connection upon cranking while on the lift and all shop lights turned off.
The ground was/is on the transaxle. I added on 25mm wide brass strap to the block.
The aluminum bell housing had arcing mark stains on it!

Take care,
Jeff Cobb


On Jul 14, 2017, at 8:45 PM, Scott Couchman via DeTomaso <detomaso at server.detomasolist.com> wrote:

> I second Charlie's ground wire suggestion. I use a dedicated cable the size of my finger from the ground lug all the way back to the started! I don't remember the wire number, but it's bigger than 1/4" in diameter! I don't have a grounding problem with my starter!
> 
>> On Jul 14, 2017, at 10:55 AM, Charles McCall <charlesmccall at gmail.com> wrote:
>> 
>> One more for the "start with the basics-basics" category. 
>> 
>> Mine had been getting harder and harder to start when hot. Making a long
>> story short, then it got harder and harder to start when cold. At the last
>> safety inspection I had to get a push to start the engine :-( 
>> 
>> Bought a new battery and it spins like mad, both hot and cold! Doh! 
>> 
>> Conventional Wisdom also suggests running a heavy duty ground wire from the
>> starter, since this is a common weak area. Two suggestions from here...
>> 
>> -----Original Message-----
>> From: DeTomaso [mailto:detomaso-bounces at server.detomasolist.com] On Behalf
>> Of Mike Drew via DeTomaso
>> Sent: viernes, 14 de julio de 2017 13:13
>> To: Robert Stroj <npdrs at maui.net>
>> Cc: detomaso at server.detomasolist.com
>> Subject: Re: [DeTomaso] Slow cranking when hot
>> 
>> Robert,
>> 
>> My Pantera did that when I first bought it and it drove me nuts. It would
>> spin like crazy when cold, but wouldn't turn over when hot. It took at least
>> 20 minutes to get gas as a result, and when I stood on the brakes stopping
>> for a red light and the motor flooded and died, I would then block the
>> intersection for a good while--not fun!
>> 
>> In my case the culprit was a bad battery. I had it tested when I first got
>> the car and was told it was still good so I spent months searching for
>> another explanation. I eventually circled back and had it tested again
>> elsewhere, with a better tester, and this time it tested bad. 
>> 
>> A new battery would have fixed it but I sent the car off for restoration
>> instead so it had a new everything. 
>> 
>> Your car has a hot motor with forged pistons, no? Those expand at a greater
>> rate than the iron block so they need to be set up a bit loose when cold. So
>> your starter has a much easier job then. After they heat up and expand,
>> piston ring drag on the cylinder walls increases and that might explain the
>> difference?
>> 
>> Try jump starting when it's hot. If it turns right over, that's a good sign
>> the battery is toast. 
>> 
>> Mike
>> 
>> Sent from my iPhone
>> 
>>> On Jul 13, 2017, at 23:36, Robert Stroj <npdrs at maui.net> wrote:
>>> 
>>> Hi, I am just touring trough Dolomites and car is running fantastic!
>>> One annoying thing I never experienced before is very slow cranking if car
>> is hot (for example after refueling). It cranks so slow that it barely
>> starts.....when cold or if left 30 minutes to cool down it cranks great!?
>>> Any experience with similar behavior, what to look for?
>>> Already got the hi torque starter and 180 degree headers, so my headers
>> are pretty far from the starter.
>>> 
>>> Thanks, Robert 
>>> 
>>> 
>>> _______________________________________________
>>> 
>>> 
>>> Detomaso Email List is not managed by POCA
>>> Posted emails must not exceed 1.5 Megabytes
>>> DeTomaso mailing list
>>> DeTomaso at server.detomasolist.com
>>> http://server.detomasolist.com/mailman/listinfo/detomaso
>>> 
>>> To manage your subscription (change email address, unsubscribe, etc.) use
>> the links above.
>>> 
>>> Members who post to this list grant license to the list to forward any
>> message posted here to all past, current, or future members of the list.
>> They also grant the list owner permission to maintain an archive or approve
>> the archiving of list messages.
>> _______________________________________________
>> 
>> 
>> Detomaso Email List is not managed by POCA
>> Posted emails must not exceed 1.5 Megabytes
>> DeTomaso mailing list
>> DeTomaso at server.detomasolist.com
>> http://server.detomasolist.com/mailman/listinfo/detomaso
>> 
>> To manage your subscription (change email address, unsubscribe, etc.) use
>> the links above.
>> 
>> Members who post to this list grant license to the list to forward any
>> message posted here to all past, current, or future members of the list.
>> They also grant the list owner permission to maintain an archive or approve
>> the archiving of list messages.
>> 
>> _______________________________________________
>> 
>> 
>> Detomaso Email List is not managed by POCA
>> Posted emails must not exceed 1.5 Megabytes
>> DeTomaso mailing list
>> DeTomaso at server.detomasolist.com
>> http://server.detomasolist.com/mailman/listinfo/detomaso
>> 
>> To manage your subscription (change email address, unsubscribe, etc.) use the links above.
>> 
>> Members who post to this list grant license to the list to forward any message posted here to all past, current, or future members of the list. They also grant the list owner permission to maintain an archive or approve the archiving of list messages.
> 
> _______________________________________________
> 
> 
> Detomaso Email List is not managed by POCA
> Posted emails must not exceed 1.5 Megabytes
> DeTomaso mailing list
> DeTomaso at server.detomasolist.com
> http://server.detomasolist.com/mailman/listinfo/detomaso
> 
> To manage your subscription (change email address, unsubscribe, etc.) use the links above.
> 
> Members who post to this list grant license to the list to forward any message posted here to all past, current, or future members of the list. They also grant the list owner permission to maintain an archive or approve the archiving of list messages.



More information about the DeTomaso mailing list